Key technology of ADSS fiber optic cable

All-dielectric self-supporting optical cable (referred to as ADSS optical cable) is a non-metallic optical cable composed of all dielectric materials, containing the necessary support system, and can be directly suspended on the power pole tower, which is mainly used for the communication route of overhead high-voltage transmission system, and can also be used for communication lines
in overhead laying environments such as lightning frequent areas and large spans.

Self-supporting type means that the reinforcing components of the optical cable itself can withstand its own weight and external load
.
This name points out the use environment of this optical cable and its key technology: because it is self-supporting, its mechanical strength is crucial; The use of all-dielectric materials is because the optical cable is in a high-voltage and high-current environment and must be able to withstand the influence of strong electricity; Since it is used overhead on the power pole tower, there must be a matching pendant to fix the optical cable on the
pole tower.
That is, ADSS optical cable has three key technologies: optical cable mechanical design, suspension point determination and supporting fittings selection and installation
.

Mechanical properties
of ADSS fiber optic cables.

The mechanical properties of optical cables are mainly reflected in the maximum operating tension, average operating tension and ultimate tensile strength of optical
cables.
The national standard for ordinary optical cables clearly stipulates the mechanical strength
that optical cables with different use modes (such as overhead, pipeline, direct burial, etc.
) should have.
The ADSS optical cable is a self-supporting overhead optical cable, so it must withstand the long-term action of its own gravity, and must also be able to withstand the baptism of the natural environment, such as strong wind, scorching sun, rain, snow and frost
.
If the mechanical performance design of ADSS optical cable is unreasonable and incompatible with the local weather, the optical cable will have potential safety hazards and the life will be reduced
.
Therefore, for each ADSS optical cable project, professional software must be strictly designed according to the natural environment and span of the optical cable routing to ensure that the optical cable has sufficient mechanical strength
.

Determination
of ADSS fiber optic cable suspension point.

Since ADSS optical cables dance with high-voltage power lines, their surface is required to be as resistant to ultraviolet radiation as ordinary optical cables, and it is also required to withstand the test
of high-voltage and strong electric environments for a long time.
The capacitive coupling between the cable and the high-voltage phase line and to the earth creates different spatial potentials
on the surface of the cable.
Under the action of rain, snow and frost and other meteorological environments and dirt, the potential difference in the wet and dirty optical cable surface local leakage current, the thermal effect generated makes part of the surface of the optical cable water is evaporated, in the moment of evaporation, the leakage current is interrupted to produce arc and large thermal energy, the accumulated heat energy will burn the surface of the optical cable, forming dendritic traces, which is the so-called electric trace.

Over time, the outer sheath is damaged by aging, and the mechanical properties of aramid yarn aging deteriorate from the surface to the inside, and eventually the optical cable will break
.
At present, this problem
is mainly addressed from two aspects.
First, a special tracking resistant sheath material is used to extrude the outer outer sheath of aramid yarn, that is, AT tracking sheath is used to reduce the tracking corrosion of the surface of the optical cable by strong electricity; In addition, the spatial potential distribution on the power pole tower is calculated by professional software and the electric field strength distribution map is drawn, and the specific hanging point of the optical cable on the pole tower is determined according to this scientific basis, so as to avoid the stronger electric field effect of the optical cable
.

ADSS fiber optic cable installation fittings
.

The fixing of the ADSS fiber optic cable on the pole tower is done
by installing fittings.
Installation fittings must be used with optical cables, and the fittings used for optical cables with different towers, different spans, and different outer diameters are different
.
Therefore, when designing, what kind of fittings are used on each tower, which towers are connected, and the length of each optical cable disc should be designed in place
.
If the fittings are not selected properly, serious problems
such as loose optical cables or broken fibers may occur.